https://draftable.com https://draftable.com is my go-to tool in this space. It understands text flow and the difference between structural and formatting differ

https://draftable.com https://draftable.com is my go-to tool in this space. It understands text flow and the difference between structural and formatting differences, and is amazing when given PDFs of legal docs that you need to retroactively get a redline for. Incredible tool, free but not open source.